what determines the colour of an egg yolk

[meriad]

I made myself some scrambled eggs this morning - using free range eggs from Asda and the scrambled egg is nearly white, the yolks were so pale. Yet other times when I've bought the same type of egg (ie not organic 'just' free range) I get a nice yellow batch of scrambled egg.

So what decides the colour of the yolk? Is it the food they eat as well as the breed or...?

just wondering

[Workingman]

I have always though that it was down to diet more then anything else. That would sort of leave free range birds more open to variations in yolk colour than their caged cousins. The free rangers can scrat about for their food; whereas the caged birds are fed industrial nutritionally and chemically controlled pellets.

I have a sensitivity to something in commercial chicken feed, which makes the yolks taste metallic - it is not a nice taste. I also detect it in some free rangers that have their range food supplemented.

Luckily the local farm shop's birds are running about in the yard and stables areas. Goodness knows what they eat, but their eggs taste good.

[Weka]

Diet mostly. I think breed may have an effect too.